PLEASE HELP ME with my frustrating 1967 Tremec conversion

"Jason O'Brien" wrote

Sounds like your pinion angle is ALLLLLLLL FUGGED UP! A common problem with that tranny conversion. To really fix it you have to cut up your tranny tunnel and fab up a new one which allows the tranny to sit with the ass end higher, thus fixing your vibration problem. There simply isn't enough room to fit that tranny in that tunnel without dropping the tailend of the tranny too low. Not so low that it doesn't work, but not high enough to keep the pinion angle close to 3 degrees on each end like it should.

Thanks for the input. I really appreciate it.

How do I measure the pinion angle?

66 6F HCS wrote:

I don't have any specific links and I don't even screw with trying to do my own driveline work. I don't know enough, I admit. You should be able to find abundant sources on the internet though. The reason I know about the problem with these tranny swaps is because I have thought of doing the same and did my research. I decided against it because of the very problem your having. I'm going the AOD route.

I will have to look around. Best of luck with the AOD swap. If I weren't so deep into this already, I'd probably consider a top loader with a Gear Vendors OD unit (although, that might create these same problems).

Thanks again!

"Jason O'Brien" wrote

Actually the GV unit is good, but pointless for our fords with the availability of OD trannies that easily swap in to our classic iron. The GV unit is WAY expensive for something that's only going on the street. Now the GV unit WOULD be useful behind the AT's put behind so many big MoPar's. I had a '68 Fury III 2 dr. Fastback with a 383 BB and the 727 torqflite tranny. No OD swap available. THAT'S when a GV unit looks good.

Sorry for getting into this late. What rear ratio do you have?

Sitting still, you should have about an inch or so.

I don't know anything about Tremecs, sorry.

Right now, your best course of action is to find a local driveshaft shop and let them see what's happening. The yoke may be worn or the shaft out of balance or whatever. They might be able to measure your pinion angle, which should be about 2º negative on a street car with a small block. If not, there is a device for this which you might find at a speed shop or at the Powerhouse tools site. Most of the nighborhood tool stores carry a cheap little plastic "angle finder". if you spend a few minutes monkeying around, you may be able to use that to dial in your pinion angle. Be aware that wedges are available that fit in the leaf spring perches to correct angles that are way off. Whatever you do, don't drive around on a positive angle.

For those others reading this, there have been articles in the Mustang magazines on properly spec'ing out a d-shaft and pinion angle. I'm sure someone here with hi-speed and a search engine might be able to find this on a Web page somewhere . You guys want to help the newbies; this is how you do it.

Keep in mind, swapping to an overdrive trans in a carbureted small block takes some forethought. Carbs are not efficient in the normal rpm range that EFI/OD cars use. A 30% overdrive will put a 4.11 ratio at

2.80, which is still too numerically low for a carbed 289/302 unless a majority of mileage is accrued at highway speeds. On the street, this setup will actually have a negative affect on mileage figures, as the engine will be in bog mode most of the time, and it is turning over the additional internal mass of the OD trans. Short duration camshafts, carbs with small primaries, unported heads, and a hot ignition will help to a point, but will hinder top speed as the engine will not be able to move enough air to overcome drag.

Carbed SBF's like rpm's. They cannot be thought of in the same terms as the later EFI engines. In my opinion, OD ratios under 3.25 are not the best choice. The way to increase mileage in these cars is to make it work less during normal acceleration, and employ OD to put it in the rpm that the factory deemed most efficient for highway use. This means a rear gear ratio of 4.30 to 4.56, depending on tire height, as compared to the OEM tires.

I know this sounds a little different, but look at the current 4.6. With insufficient factory torque and increasing vehicle weight, some guys have eschewed the 'traditional" swap to 3.73's in favor of 4.10's, and have discovered that there was no "hit" in mileage, and the engine works less around town. And, top speed is not much affected.

Not at all! Thanks for your input. I run 3.80 gears.

Ok... that helps establish one point of reference... great.

Yeah, I think I need to bring it somewhere.

I did research pinion angle on the web, after 66 6F HCS's post, and I did go buy a magnetic angle finder from the hardware store. My best attempts at determining pinion angle (I took several measurements and averaged, to make sure I factored out as much error as possible) showed

6º negative. I was confused, because I saw recommendations of 5-7º degrees, but couldn't imagine this would apply to -all- leaf-spring-equipped cars with -all- V8s. It seemed rough, but then again, mine was at 6. I trust Currie with his 2º recommendeation (for obvious reasons, and I run a Currie rear end too). The angle of the driveshaft was "up" 2-3º, and the angle of the pinion flange was "down" 3-4º. It sounds like I need to establish the angle at the transmission also, then make some adjustments. It sounds like I also need to establish yoke travel and ensure the shaft is not too long.

I have had issues with tuning I didn't have before the swap. I have had to advance the timing to about 12º BTDC, re-curve the distributor to advance completely by around 2800, and get different step-up springs and jets for my Edelbrock 600, adjust idle mixture, etc. It's been a process of continual fiddling and asking a lot of questions, but I am now very close. It still surges a -little- bit, but it starts well, doesn't foul plugs, doesn't run too hot, or ping; it gets around-town gas mileage comparable to what it did with the auto (it revs higher on average now) and doesn't bog - so long as I shift between 2500 - 3000 and cruise at 2000 minimum. I have stock heads and a Comp Xtreme Energy cam with total duration 256, but intake duration 212 @ 0.050", exhaust duration 218 @ 0.050". Its advertised range is 1000-5200. And it seems to wave goodbye right around 5200. Oh, stock manifolds... I need to get hi-po's or shorties...

Interesting... sounds like I am somewhere in the middle, and have found out a few things you've mentioned through just driving the thing and fiddling with it. Driving in 5th, it has enough torque at 2500 to cruise at 75, but I don't have much in terms of acceleration, partially due to the high amount of wind drag the 67 creates. I have noticed the vacuum drops fairly drastically (I have a gauge) in 5th with even a blip of throttle. If I want any appreciable acceleration over 60, I have to use 4th, period.

Thanks again for all your input, and thanks also to 66 HCS for his posts. I sincerely appreciate it. I will let you know how things go with the drivetrain adjustments.

Jason

So your final drive is around 2.66. I'm guessing the Tremec has a .7

5th.

I expounded more on this is another post, if you saw it.

Yep.

Another option I mention from time to time here is using 351W manifolds. They flow probably as well or better than the hi-po's, and are usually lying around in the dirt at the junkyard. Look for car units, as the truck pieces may not have the right exit angle.

Yep. BTW, torque comes into play upon acceleration. Maintaining a steady speed is the job of horsepower. Watching your vacuum gauge at higher speeds in 4th gear should give you the sweet spot (highest reading) for your engine. Ideally, you would adjust gearing to give you that rpm range at 75 or so in 5th.

Another tidbit, which may not apply to you, is to watch the vac reading under full acceleration in low gear up to the top of your power band. If the reading never quite gets to zero, then the carb could be too small, or the secondaries aren't opening correctly.

OK. Good luck with it all.

So, overall AOD gearing... with a 289 4v A Code 225 hp 8" stock tracloc rear, 24.5" (might be 24.25") tires, I need somewhere in the neighborhood of 4.3-4.7 to achieve a balance between good highway and around town without taking too big a hit in fuel economy for either pavement? Or did I miss read?

Time for this old dog to learn another new trick ; )

V'ger jma(NOSPAM)@snowcrest.net

1965 Mustang Fastback 2+2 Vintage Burgundy w/ Black Std Interior 289 ci 4v V8 oem A Code Dual Exhaust C4 Auto converted to AODE 8" Trak Lok Vintage 40 wheels BF Goodrich gForce T/A 225/50ZR-16 KDWS tires Built in San Jose, CA on my birthday, May 10th ; ) Restoration by: Cool Mustang Restorations Cool, CA

Woof, woof woof woof. Oh wait, let me turn on the translator:

Actually, the only two choices in the 8-inch are 4.11 and 4.62, the latter coming out to 3.14 in 4th. You may be able to use the 4.11's, considering your tires are shorter than stock and a truly stock A-code would be using 2" exhaust pipes. However, the AOD will soak up more power than a C4. I'd go with the .62's and pattern a build after Jason's engine, personally. A non-computer AOD (as opposed to the AODE you mentioned in the other group) would need a shift kit at least, to up the shift points a bit. The grin factor from this setup should be pretty high.

.68 actually, but yes, it's tall.

I did, thanks...

Believe me, I'm going to pounce on this. I have been nagged by this problem for far too long. The intent of the car is to be used as a driver / Sunday cruise car, and I don't drive it too much because I fear damage is occurring. It is very frustrating b/c I have spent a lot of time and money on this project. Many others are in my shoes, I'm sure... just can't give up...

Thanks for the recommendation. I know this is also a subject of enternal debate, and I've heard people recommend these before. And I am very familiar with the trouble others have had with proper fit, performance, cracking, and getting to spark plugs with aftermarket headers.... why I've stuck with the old log style manifolds so far... and hi-po's are expensive

I sometimes forget torque is a force and hp a rate equation... yeah, it seems a bit tall. Right at 3000 rpm seems to be that spot for my motor, which works out to just over 90 in 5th. Not a cruise speed... It seemed odd how strong it feels in every other gear compared to 5th, even though it's overdriven 32%. I was used to EFI. I didn't really think about carbed SB's needing more RPM to be efficent, but it makes sense, just from seat-of-the-pants experience anyway...

It does... I have good seals and the carb functions properly. Just needed some extra fiddling. Glad I put that gauge in, it helps with diagnosing things..

Thanks again, and best of luck with your projects. I'll post some results soon.

Personally, I'm trying to stay away from "electronics"

Exhaust is stock a code (the change was from the Holly to the Edlebrock.

The tires are the gforce indicated below, and I think I was informed they were 24.25 but would have to recheck to make sure.

Shift kit.... as l>>

V'ger jma(NOSPAM)@snowcrest.net

1965 Mustang Fastback 2+2 Vintage Burgundy w/ Black Std Interior 289 ci 4v V8 oem A Code Dual Exhaust C4 Auto converted to AODE 8" Trak Lok Vintage 40 wheels BF Goodrich gForce T/A 225/50ZR-16 KDWS tires Built in San Jose, CA on my birthday, May 10th ; ) Restoration by: Cool Mustang Restorations Cool, CA

You mentioned an AODE in the other group. The E is for electronic. What you want to build is an AOD with certain AODE and maybe 4R70W parts in it.

Well, there has to be a way for you to lock out overdrive, and yu need to install a TV cable kit.

I'm going to tell you my own outlook on this overdrive thing, which you and other may not agree with.

I don't think it's necessary if all you want it for is mileage. The whole OD thing came about from the factory in order to squeak out more EPA mileage points. The only way they could actually make it work was to design EFI systems to go along with it, because as we see carbs don't like low r's. So aong came all this crap tacked on to the motor and....well, I digress.

Anyway, about 3 years ago or so, Car Craft had an article that proved what I had been saying. They did a study of several OD swaps and the results for number crunching. Factoring in the average cost of a new trans, kit and labor, against the average increase in mileage (not much), they estimated that it would take 100,000 miles driven before you *break even* with the swap monetarily. And, they did not even mention the power loss from the OD trans. There can be as much as a 30 hp drop going to an AOD over a C4. That's a lot of power that the little motors really could use otherwise.

Back when I ran my '68 with a 289 and a stick, it had 4.11's in it. The bottom end was stock with cast pistons. I drove the freeway all the time at 75+. I trapped the quarter at 105. Nothing ever came apart or overheated. I raced on the street and general beat the shit out of it. When I tore it apart, it was cherry.

The C4 is a good trans when properly built. OD's don't really start looking good for carbs until you start getting into bigger inches.

Just my opinion.

Good input. Thanx. In 1970-71 I had a 65 FB with 289 2v all stock. Sucker ran like the wind on the strrets of Seattle and up and down the I5 Corridor. I made a really long trip from Seattle down the California coast route and back and the worst thing (aside from the snowstorm in the high mountain passes) was the seating). I never had any problem with it under any conditions ('cept black ice and a bridge rail).

This car is essentially the same as my first; mostly stock; though I changed the wheels and tires to 16" Z's, added HD radiator and shroud along with flex fan. And it's a 4v vs the 2v I had before. I did add the tracloc as well.

I've been through a lot of vehicles since then. When I wanted to get back into a classic, I started reading everything I could find on the subject. Everywhere I turned, all the writings said convert to AOD/AODE as one of the top 10 things needed to be done. Something about the noise levels driving the driver bonkers on the open road with the stock C4 and the bigger wheels. (I'd have to drag out the articles to properly quote them. That's where that AOD idea came from.

I did read an article by Mustangs Plus where on a long trip to a show, they took a carbed 'stang and an EFI stang, and there wasn't a heck of a lot of difference in mileage.

Now, if I really don't need to convert the tranmission, I can think of a few things that money could go toward... like some decent seats.... and maybe even some more horses with an updated cam, etc.

So, maybe I'll just hold off on the AOD and drive it a while and see.

So, thanks mucho. Any more ideas, whether others agree or not... I always willing to listen and try to learn.

V'ger jma(NOSPAM)@snowcrest.net

1965 Mustang Fastback 2+2 Vintage Burgundy w/ Black Std Interior 289 ci 4v V8 oem A Code Dual Exhaust C4 Auto converted to AODE 8" Trak Lok Vintage 40 wheels BF Goodrich gForce T/A 225/50ZR-16 KDWS tires Built in San Jose, CA on my birthday, May 10th ; ) Restoration by: Cool Mustang Restorations Cool, CA

Well, tires with shorter sidewalls will surely add to the noise. The extra rpm's shouldn't bother those who *like* the sound of a classic V8. If you want a quiet car, there are modern sound deadening material that you can put under your carpet and in your doors. OEM-style muffs are quiet. Kinda kills the experience, though.

See?

Now you're thinkin'. Those early seats are a pain in the ass. Literally.

A C4 with a TRANSGO shift kit and 3.50's should do ya.